ABUJA, Nov. 5 (Xinhua) -- At least nine people have been confirmed killed following an accident on an intercity road in southern Nigeria, according to local police on Monday.

The police said 12 other people sustained varying degrees of injuries due to the accident which occurred Sunday night on the Enugu-Port Harcourt expressway, one of the busiest roads in Nigeria's southeast region.

Ebere Amaraizu, a spokesperson for the police in Enugu, told reporters that the accident occurred when an articulated vehicle conveying a caterpillar and a mini-bus had a head-on collision.

An investigation has been launched to further ascertain the cause of the accident, the cop said.

The Enugu-Port Harcourt expressway has been under reconstruction since last year.